


His Obsession

by Ladykey17



Category: Shall We Date?: Obey Me!
Genre: Blood, Dubious Consent, F/M
Language: English
Status: Completed
Published: 2020-07-12
Updated: 2020-07-12
Packaged: 2021-03-04 19:33:53
Rating: Mature
Warnings: Graphic Depictions Of Violence, Rape/Non-Con
Chapters: 1
Words: 2,897
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25221715
Author URL: https://archiveofourown.org/users/Ladykey17/pseuds/Ladykey17
Summary: He knew he was wrong, but didn't know how to make it up to you. When he tried, you pushed him away.Why do humans have to make such stupid decisions?
Comments: 2
Kudos: 43





	His Obsession

**Author's Note:**

> A birthday gift to my bestfriend, who's a hardcore, Yandere Belphegor lover. 
> 
> Please mind the tags. 
> 
> Comments are always appreciated!

Every day was the same exact thing. She’d come down to the kitchen for breakfast, and joke with his brothers as if everything was fine. She’d play games with Levi, and chat with Satan in the library, cook in the kitchen with Beel, and fail to keep him from eating all the ingredients. She’d spend time tutoring Mammon, gossip with Asmodeus, and kiss up to Lucifer...It was a pattern. Maybe not the same time every day, but she did everything in her power to spend time with everyone on the student council. 

_ Everyone but me.  _

He had to admit, maybe killing her wasn’t a good idea, and trying to kill her again wasn’t smart either...but who hasn’t committed a murder? She was in the Devildom, what did she expect? To the best of his knowledge, she was warned several times to stay away from the attic, she didn’t listen. 

_ Just like a stupid human.  _

Still...This was no ordinary human. This human was related to  _ her.  _ The only woman in his life he ever gave a damn about, his Lilith. He was still having a hard time believing it. Lucifer kept her from them, he let him beat himself up for centuries over her death...and said  _ nothing  _ about it. They had to find out Lilith lived through the human.  _ I’ll get him for that.  _

But his desire for revenge was eclipsed by his desire to be near her, and not be near her at all. He knew better than to approach her after everything. Upon further reflection, humans didn’t like being murdered...no matter the timeline. 

He had to watch her from a distance, watch Mammon’s idiocracy rub off on her, and watch Levi pull her down further into the otaku rabbit hole. Those were her two favorite people to spend time with, them and Beel. In his opinion, that was her best choice of company. 

He watched her from the back of the classroom, his head on his arms while she sat in the front. She wasn’t very smart, or was that because she wasn’t from the Devildom? He did only share history with her. 

If she kept going like that, Lucifer was going to punish her.  _ I can’t let that happen.  _ He did his best to keep her safe while keeping her unaware. He stared down demons in her gym class with glowing magenta eyes and monitored her sleeping. He slept most of the day, it wasn’t like being up all night would be a big deal for him. 

She was cute, she snored...and she kept a death grip in the stuffed animal she slept with every night. He remembered her mentioning him when Mammon teased her for it, Mr. Blueberry. The idea made him smile, she had a stuffed animal she always slept with, and he had his favorite pillow. It was the only thing he had left when they were kicked out of the Celestial Realm, the pillow that he and his siblings shared when they would take a group nap. He had no clue how Asmo wrangled it out of there for him, or why, but he was appreciative. It made watching him with the human a little more tolerable. 

_ My human  _

If this girl really was related to Lilith, that means he had to know her like the back of his hand. He knew Lilith better than anyone else, so he had to know her. He had to know this human... _ his  _ human. 

And he did just that. He studied her habits, he knew her schedule, he knew she was allergic to shellfish and hated listening to Lucifer’s lectures. She was right-handed but enjoyed talking with both hands. She loved screeching bat ice cream with blood cherries, talk about being open to cultural differences. 

He enjoyed watching her destroy Levi in his games, and thought it was cute when she got frustrated when Satan danced circles around her in literary studies, but he could tell she didn’t like that. Her face would get red with frustration, and she was so pretty when he cried. Her voice always went up a few octaves, and she reminded him of Lilith. No matter how enjoyable, he had to fight the urge to pull her away from him, but he wanted to keep her safe and happy. 

After weeks of planning, he finally figured out a way. He found a way to keep his human safe from any more frustrations, from RAD’s insane homework load, from his overwhelming brothers, from all the other demons who wanted to consume her, everything. Tonight, she would be his...whether she wanted to or not. 

Cassidy smiled as she finished cleaning the kitchen. She never got tired of her shift working kitchen duty. She enjoyed seeing the brothers enjoy her cooking, and she loved how spacious the area was. She had enough room to dance while she cooked, and she would never get tired of it. 

She walked over to the window and sighed in content. Nighttime was neverending in the Devildom, but she rarely missed the sun. Her eyes lowered to look at the little bits of the city she could see from where she stood, it reminded her a bit of Paris. Sure it wasn’t as romantic, but it was full of life and lights. 

She turned to leave the kitchen and stopped when she saw the youngest demon brother. She made it her business to keep her distance from him after the incident a few weeks ago. You never really get over watching your dead body in the arms of one of your friends. “Belphegor,” she said quietly. “Do you need anything?”

The sleepy demon smiled at her a little, and that smile stirred up her insides. She was terrified, but she also felt another emotion she wasn’t quite sure how to pinpoint. He stepped closer to her, and she wasn’t able to back away since she was already next to the window. 

“I have something for you,” the demon continued. He reached into his pocket and pulled out a small box wrapped in cherry blossom fabric. “Cherry blossoms are a sign of new beginnings...and I realize I didn’t have the best beginning with you. I’d like a new one.”

“You can’t make everything better with presents, Belphie,” Cassidy said, cautiously taking the box out of his hand. “Humans don’t usually come back from being killed.”

“I know...apologizing is a little difficult for me...can this at least be a start?” He backed away from her and watched her carefully undo the fabric. He smiled when he saw the confusion on her face. “It’s a mini cowbell.” 

“I see,” Cassidy pulled out the diamond cowbell and studied it closely. Was this supposed to go on a charm bracelet? She didn’t own one of those. She could tell a lot of detail went into making it though, and when she turned it over, she smiled a little. “MB?”

“Mr. Blueberry.” Belphegor shifted his weight to his other foot and rubbed the back of his neck. “I know he’s a teddy bear, but I saw it at a store window earlier and thought you might like it.”

“It’s so cute.” Her smile widened and Belphie suddenly felt like he couldn’t breathe. She was cute when she cried, but she was beautiful when she smiled. “Thank you...everyone else kind of just makes fun of me for toting around a stuffed animal.”

“I can relate. They’re the same way about my pillow.” He gave her a sleepy smile and he nodded his head over his shoulder. “You should go put it on him, I’ll wait for you here.” 

“Okay, I’ll be right back.” He watched the girl run off to grab her stuffed animal and he chuckled.  _ She’s so adorable.  _ He quietly walked behind her and stood by the door while she fastened the bell on the teddy bear’s neck. A soft purple light would glow around him, and she would begin to yawn. 

Cassidy yawned again and held onto the edge of her bed. “Wha-?” She turned around and saw Belphegor at her door, glowing the same purple he was when he tried to kill her for a second time. She tried to scream out for Lucifer, but only managed to yawn one more time before collapsing at his feet. 

Belphegor carried Cassidy back to the attic and laid her down on the pile of pillows. The smile on his face while he watched her sleep was inevitable, she was just so adorable. He moved her hair out of her face, savoring the calm before the storm before getting to work. It was late enough that all his brothers were either sleeping or in Levi’s case, gaming with his headphones so he wouldn’t hear anything going on. 

Belphie slipped into Cassidy’s bedroom and started packing her things neatly in her suitcase. He looked over at her DDD, and sat on the bed, turning it over in his hands. He had to make it look like she left, but he was conflicted if he should trash her phone or take it with him. 

After some consideration, he decided to factory restart her phone and leave it. That made the most sense right? Why take a phone with her if she couldn’t use it? He finished packing her stuff and simply went back to the attic. He placed her bags in the corner and put a spell on the door so the door would appear to be a wall, and touching the rail would make someone forget why they were going upstairs. 

A couple of hours later, Cassidy stirred and felt pressure on her body. She opened her eyes and looked over at the youngest demon cuddling her body in his sleep. Her eyes took in the room, she remembered the attic, though not fondly. She tried to move out of his hold and her eyes widened at the sound of chains moving. “What the-” She tried to push Belphie off of her, and winced when he tightened his grip. 

“Not a chance, human.” Belphie moved his face in her neck and growled a little, enjoying her scent. “You should go back to sleep, it’s only...” He looked over at his clock and yawned. “4:00 AM.”

“Belphie what the fuck? Get off of me!” Cassidy twisted in his hold until he finally let her go. She got up and stopped when she felt the weight of the chain on her ankle. “What are you doing?”

“Giving us a new start...What does it look like?” Belphie reached out to touch her face and scowled when she backed away from him. “I’ve already lost Lilith, and then I killed you. I don’t want you getting hurt again-”

“You’re the one that hurt me!”

“And I’ve already repented for that.” Belphie reached out and pulled her by her shirt, staring down into her eyes. “This is my final act of repenting. You don’t know what kind of damage my brothers can do, the other demons? I’m trying to protect you.”

“The only person I need protection from is you!” Cassidy tried to push against him, but he jerked her into place. “Beelzebub!” 

Belphie fought back a laugh and he kissed her cheek. “You’re so cute. Beel can’t hear you. None of them can. The room is charmed and I’m the only one who can see it...Just like Lucifer did, except better.” 

Cassidy felt panic surge through her body, and she pulled at the chain on her ankle. “Belphie...This is unreasonable. You don’t need to lock me in here to keep me safe...”

“But I do...” Belphie laid back down and looked at her, his eyes full of joy. “They’ve all threatened you at one point or another...Except for Mammon...But that idiot can’t protect. This way, I can keep you safe in one place.” He moved his hand slowly down her cheek and pinched her bottom lip between his fingers. “Let’s go back to sleep.”

Cassidy refused to keep still. She hit him a few times, before spitting on him in desperation. Belphie stared at her in shock, and let go of her. His hand slowly wiped her saliva off of his face, and she backed away as far as she could from him. 

His eyes glowed a bit, and he grabbed the chain that was attached to her cuff. “You don’t want to sleep? Fine.” He yanked her back over to him, shifting to his demon form. “There’s plenty of things we can do to tire you out.”

Seeing the rage in his eyes, Cassidy felt panic spike in her. She dug her nails into the carpet and tried to hold on to anything she could to keep from being pulled closer. She did her best to land a blow to the demon’s face with her foot and choked back a scream when he grabbed her ankle and snapped it like a twig. 

“That was cute.” He grinned wickedly and pulled her up by her shirt. His hand wrapped around her throat and he kissed her deeply, allowing his fangs to bite down on the soft skin of her lips. He could hear her whining, and he moved his hand behind her back, effortlessly ripping apart the fabrics of her pajamas. 

He broke the kiss lightly and licked the blood from her lips. He chuckled and moved to her ear. “You make this any more difficult than it has to be, and you’ll wish I killed you here.” Without anything further, he pushed her down on the pile of pillows. 

Cassidy let out a small scream and tried to crawl away, but Belphie pinned her down with the weight of his body. She could feel the fabric of his pants move down against their legs, she could feel her blood boiling. She pressed her legs together and let out a soft cry, only to be muffled by a familiar stuffed blue fabric, the motion causing its little cowbell to go off. 

“You stupid humans never know how to take anything with grace.” Cassidy felt her legs forced apart and pressure on her lower body. Belphie cupped her face, his claws gently pierced her skin. 

“ _ It’s a good thing we have a food chain for a reason.”  _ Despite not knowing what he said, Cassidy felt a chill run down her spine. Demonic language was always harsh on her ears, to the point where Levi had to give her a translator for her classes. He moved one hand to her hip, stabbing her side with his claws to keep her in place. He teased her with the tip of his cock, and slowly dragged his tongue across her neck. 

He pushed himself inside of her without further warning, and laughed when she let out a muffled scream. “Fuck, so good...” He used his tail to bound her hands together behind her back. He forced her to sit up while he sat back, and started moving her up and down on his shaft.

Cassidy cried quietly, every time she tried to shift to get more comfortable, he jerked her back in place. He moved his free hand from her face to her torso, slowly dragging his claws against her stomach and hips. She could feel her blood dripping down her body, she arched her back when he started thrusting harder, the pain in her ankle simmering down to a dull burn with everything else going on. Her crying slowly slipped into labored moans. 

“There we go. It’ll be a lot more pleasant if you just relaxed and enjoyed yourself.” He reached up and grabbed her breast, squeezing roughly as he rammed into her harder. He feverishly worked his lips up her back, peppering it with kisses while his horns tore into her skin. The scream she let out caused a shutter to rip through him. He tightened his hold on her hips and did his best to suppress a roar that desperately wanted to break free of him. He bit down on her shoulder and started thrusting faster, moving his hand from her breast to her clit to work her over further. 

Lightheadedness overcame the girl. The pain in her ankle, the burning feeling on her skin from his claws, the feeling of him rubbing her clit, the power behind his thrusts, it was all too much. She pressed her back against him and slowly started bucking her hips to try and match his movements. Black spots danced in her vision, and her body clenched tightly. It wasn’t long before she was a trembling, dripping mess on his lap. He pressed her down on him once more and reached his climax, cursing her name muffly against her skin. 

Prying his fangs out of her, he laughed at the look on her face. She looked dazed, her skin bright pink. He gently pushed her off of him and got up. “Looks like that did it, huh?” He could see her eyes fluttering, the light twitching of her body, she’d be gone any second. He grabbed the soiled pillows and tossed them in the corner to be washed, then went to the back of the room and grabbed the first aid kit.

“Go ahead and get some rest, we can try this again in the morning.”


End file.
